Switching apparatuses for electrical switching devices, in particular electrical circuit breakers, are basically known. They are used for instance to safeguard line sections or current circuits. The circuit breakers can also be embodied as compact circuit breakers in the form of electrical switching devices.
To ensure that the switching apparatus is switched off in the event of short circuits or intensive current fluctuations, these are provided with tripping apparatuses. The tripping apparatuses are used to detect short circuits at one or more poles and accordingly to implement a switching of the switching apparatus (switch-off). A tripping element is provided herefor in known switching apparatuses, which is moveably supported between a rest position and a tripping position.
In the rest position, the tripping element is so-to-speak ready to implement a tripping process. If for instance a short-circuit current is perceived at a pole, the tripping element is moved into the tripping position so that, based on this movement, a switching mechanism is set into operation. In this embodiment of known switching apparatuses, an electric, magnetic or thermal transmission from the tripping element is used to transmit the tripping information for instance. It should be noted here that spring mechanisms are frequently used, which allow the tripping force to be adjusted for a tripping element.
In this process, when monitoring more than one pole, for instance with direct current having two poles or with alternating current having at least three poles, a plurality of such spring elements is needed. It should however be ensured that when monitoring at least two poles, the same or essentially the same tripping force is set for all poles. Aside from the increased complexity on account of a plurality of individual spring elements, these spring elements must be attuned to one another as well in respect of their fine tuning for the tripping forces.
A further disadvantage of known switching apparatuses is that the passing on of the tripping movement to a tripping mechanism, for instance a switch of the switching unit, also has to take place separately by each individual tripping element. The complexity and the costs of known switching apparatuses are therefore also significantly increased here.